title: Validation of the charm 3 SL3 beta-lactam test for screening raw milk in compliance with the U.S. pasteurized milk ordinance. Performance Tested Method 071002.
abstract: The Charm 3 SL3 beta-Lactam Test is a 3 min receptor-based lateral-flow Rapid One-Step Assay (ROSA) that detects the six beta-lactam drugs of concern approved for dairy cattle in the United States. The method is a biochemical formulation change of the SL3 beta-Lactam Test evaluated and approved in 2007. The Charm 3 SL3 was evaluated under the AOAC Research Institute Performance Tested Method (PTM) program following the protocol of the U.S. Food and Drug Administration, Center for Veterinary Medicine. The method was approved as PTM 071002 on May 8, 2009. The following drugs were detected in three combined lots: penicillin G at 3.8 ppb, ampicillin at 8.0 ppb, amoxicillin at 8.4 ppb, cephapirin at 20.0 ppb, ceftiofur (total metabolites) at 79 ppb, and cloxacillin at 8.6 ppb > or = 90% of the time with 95% confidence. These detection levels are lower than, but within 75% of, the U.S. Safe Level/Tolerances. Lot-to-lot repeatability was typically within 20% of these determined levels. The test kit was found to be suitable for testing thawed frozen samples. It was also found to respond with equal or better sensitivity to samples that contained incurred analytes, i.e., both the microbiologically active parent drug and its active metabolites. There were no interferences from somatic cells at 1.1 million/mL, bacterial cells at 300 000 CFU/mL, or 32 other non-beta-lactam drugs at 100 ppb. Ruggedness experiments indicated that the test procedure is robust. These results meet the fit-for-purpose approval criteria for inclusion in the National Conference for Interstate Milk Shipments milk testing program.
authors.affiliation: Charm Sciences Inc., 659 Andover St, Lawrence, MA 01843, USA. bobs@charm.com
authors.forename: Robert S
authors.initials: RS
authors.lastname: Salter
authors.forename: David
authors.initials: D
authors.lastname: Douglas
authors.forename: Lindsey
authors.initials: L
authors.lastname: McRobbie
authors.forename: Julio
authors.initials: J
authors.lastname: Quintana
authors.forename: David
authors.initials: D
authors.lastname: Legg
authors.forename: Janine
authors.initials: J
authors.lastname: Schwartz
authors.forename: David
authors.initials: D
authors.lastname: Conaway
authors.forename: Carla
authors.initials: C
authors.lastname: McPhee
authors.forename: Steven
authors.initials: S
authors.lastname: Saul
authors.forename: Robert
authors.initials: R
authors.lastname: Markovsky
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis; D002417:Cattle; D005504:Food Analysis / Q000331:legislation & jurisprudence / Q000379:methods* / Q000592:standards; D005506:Food Contamination / Q000032:analysis* / Q000331:legislation & jurisprudence*; D008892:Milk / Q000737:chemistry*; D011786:Quality Control; D014481:United States; D047090:beta-Lactams / Q000032:analysis*
chemical_list: D000900:Anti-Bacterial Agents; D047090:beta-Lactams